tikzlibrarynorm.code.tex

\tikzset{
	Norm/.code={%
		\pgfmathparse{#1}%
		\edef\qrr@tikz@norm{\pgfmathresult\ifpgfmathunitsdeclared pt\fi}%
		\let\ifqrr@tikz@normcs@unitsdeclared\ifpgfmathunitsdeclared},
	Norm=1,
	norm/.style={to path={-- ++(norm cs: \tikztotarget\space from \tikztostart) \tikztonodes}}
}
\newif\ifqrr@tikz@normcs@unitsdeclared
\newdimen\qrr@pgf@normcs@from@x\newdimen\qrr@pgf@normcs@from@y
\tikzdeclarecoordinatesystem{norm}{%
	\begingroup
		\let\qrr@next\relax
		\pgfutil@in@{ for }{#1}%
		\ifpgfutil@in@
			\qrr@tikz@normcs@parse@for#1\@qrr@tikz@normcs@parse@for
		\else
			\def\pgf@tempa{#1}%
		\fi
		\edef\pgf@marshal{\noexpand\pgfutil@in@{ from }{\pgf@tempa}}\pgf@marshal
		\ifpgfutil@in@
			\expandafter\qrr@tikz@normcs@parse@from\pgf@tempa\@qrr@tikz@normcs@parse@from
			\let\qrr@next\qrr@tikz@normcs@calc@hard
		\else
			\let\qrr@tikz@normcs@parse@to\pgf@tempa
			\qrr@pgf@normcs@from@x\z@
			\qrr@pgf@normcs@from@y\z@
		\fi
		\expandafter\qrr@tikz@normcs@parse@@to\expandafter{\qrr@tikz@normcs@parse@to}%
}
\def\qrr@tikz@normcs@calc@easy#1{%
	\pgf@xx\@ne
	\pgf@yy\@ne
	\pgf@xy\z@
	\pgf@yx\z@
	\tikz@scan@one@point\pgfutil@firstofone(#1)\relax
	\pgf@xa\pgf@x\pgf@ya\pgf@y
}
\def\qrr@tikz@normcs@calc@hard#1{%
	\tikz@scan@one@point\pgfutil@firstofone(#1)\relax
	\pgf@xa\pgf@x\pgf@ya\pgf@y
	\advance\pgf@xa-\qrr@pgf@normcs@from@x
	\advance\pgf@ya-\qrr@pgf@normcs@from@y
	\pgfpointnormalised{\pgfqpoint{\pgf@xa}{\pgf@ya}}
	\pgfmathsetlength\pgf@xa{\pgf@yy*\pgf@x-\pgf@yx*\pgf@y}
	\pgfmathsetlength\pgf@ya{-\pgf@xy*\pgf@x+\pgf@xx*\pgf@y}
}
\def\qrr@tikz@normcs@calc@unit#1{%
	\tikz@scan@one@point\pgfutil@firstofone(#1)\relax
	\pgf@xa\pgf@x\pgf@ya\pgf@y
	\advance\pgf@xa-\qrr@pgf@normcs@from@x
	\advance\pgf@ya-\qrr@pgf@normcs@from@y
	\pgfpointnormalised{\pgfqpoint{\pgf@xa}{\pgf@ya}}
	\pgf@xa\pgf@x\pgf@ya\pgf@y
}
\def\qrr@tikz@normcs@parse@@to#1{%
		\ifqrr@tikz@normcs@unitsdeclared
			\let\qrr@next\qrr@tikz@normcs@calc@unit
		\else
			\ifx\qrr@next\relax
			  \pgfutil@in@{cs:}{#1}%
			  \ifpgfutil@in@
			    \let\qrr@next\qrr@tikz@normcs@calc@hard
			  \else
			    \pgfutil@in@{intersection }{#1}%
			    \ifpgfutil@in@
			      \let\qrr@next\qrr@tikz@normcs@calc@hard
			    \else
			      \pgfutil@in@|{#1}%
			      \ifpgfutil@in@
			        \let\qrr@next\qrr@tikz@normcs@calc@hard
			      \else
			        \pgfutil@in@:{#1}%
			        \ifpgfutil@in@
			          \let\qrr@next\qrr@tikz@normcs@calc@easy
			        \else
			          \pgfutil@in@,{#1}%
			          \ifpgfutil@in@
			            \let\qrr@next\qrr@tikz@normcs@calc@easy
			          \else
			            \let\qrr@next\qrr@tikz@normcs@calc@hard
			          \fi
			        \fi
			      \fi
			    \fi
			  \fi
			\fi
		\fi
		\qrr@next{#1}%
		\pgfmathatantwo{+\pgf@xa}{+\pgf@ya}%
		\ifqrr@tikz@normcs@unitsdeclared
			\edef\pgf@marshal{\noexpand\pgfpointpolar{\pgfmathresult}{\qrr@tikz@norm}}
		\else
			\edef\pgf@marshal{\noexpand\pgfpointpolarxy{\pgfmathresult}{\qrr@tikz@norm}}
		\fi
		\pgfmath@smuggleone\pgf@marshal
	\endgroup
	\pgf@marshal

}

\def\qrr@tikz@normcs@parse@from#1 from #2\@qrr@tikz@normcs@parse@from{%
	\def\qrr@tikz@normcs@parse@to{#1}%
	\tikz@scan@one@point\pgfutil@firstofone(#2)\relax
	\qrr@pgf@normcs@from@x\pgf@x
	\qrr@pgf@normcs@from@y\pgf@y
}
\def\qrr@tikz@normcs@parse@for#1 for #2\@qrr@tikz@normcs@parse@for{%
	\def\pgf@tempa{#1}%
	\pgfkeysalso{/tikz/Norm={#2}}%
}

% a fix for the 2.10 version of PGF/TikZ
\expandafter\let\expandafter\pgfmathatantwo\csname pgfmathatan2\endcsname